Paper machine

ABSTRACT

A paper machine where the press section features exclusively double felt roll presses (13-16; 23-26) through which proceeds the paper web (10) to be dehydrated between two felt belts (15,16; 25, 26). The paper web (10) is constantly supported by a backing belt (34) at least in the first drying group of the drying section. The transition of the paper web (10) from one roll press to the next and from the press section to the drying occurs without an open draw. The first drying cylinder (31) is located outside the backing belt loop (34), with the paper web (10) proceeding across the upper cyliner area of this drying cylinder (31). The entrance point of a rope carrier (45,46) (serving to thread the paper web into the drying section) is located behind the leaving point of the paper web (10) from the first drying cylinder (31).

TECHNICAL AREA

The invention concerns a paper machine which is intended to be suitedpreferably for the production of mass papers (for instance printingpaper, corrugated liners or similar) at maximum operating speeds.

STATE OF THE ART

1. DE-OS No. 33 33 040

2. WO No. 82/02937;

3. DE-PS No. 287 998;

4. DE-AS No. 25 38 846

5. DE-AS No. 23 65 438 (similar to U.S. Pat. No. 4,000,035);

6. WO No. 83/00514;

7. DE-OS No. 32 36 576.

The invention is based on the paper machine known from document 1. Onthat machine, the paper web runs successively through several press gapsand thereafter into the drying section, after it has been transferredfrom the web-forming screen with the aid of a felt belt. In each of thepress gaps the paper web is located between two felt belts and is thusnot in direct contact with any of the press rolls. Therefore, none ofthe press rolls needs to be a stone roll. (As generally known, a stoneroll would in many cases have to be made from natural stone, causingextremely high cost. Besides, only a relatively low press force can beapplied when using stone rolls.) Another advantage of the prior papermachine is that the paper web proceeding through the press section andtransfering from the press section to the drying section is constantlysupported by at least one of the felt belts and/or by the backing beltof the drying section, so that the still wet paper web is considerablyless stretched in longitudinal direction than in other prior papermachines where an open draw exists between the press section and thedrying section.

A similar prior paper machine is described in document 2. On thismachine, the paper web runs together with the backing belt of the dryingsection first across the lower cylinder area of a first drying cylinderlocated within the backing belt loop. The arrangement according todocument 1 is different: the paper web proceeds together with thebacking belt first across the upper cylinder area of the first dryingcylinder which is located outside the backing belt loop.

A disadvantage of the designs known from documents 1 and 2 is that thefirst "threading" of the paper web into the drying section (after ashut-down or web break) causes serious difficulties. Documents 1 and 2do not mention this problem. The teaching of documents 3 and 4 is that arope carrier be provided in the drying section with the aid of which anarrow edge strip of the paper web, the so-called transfer strip, isfirst introduced into the drying section. The remaining part of thepaper web is passed from the web-forming screen or from one of the pressrolls into a scrap container during this threading phase. Next, thetransfer strip is broadened until it has assumed the width of the fullpaper web. As generally known, the rope carrier is located on thetending edge of the drying cylinders, and at that, outside the paper webwidth, with the entrance point into the rope carrier being arranged onor before the first drying cylinder. For that reason, the transfer stripmust be deflected sideways from its normal path before the entrancepoint of the rope carrier (i.e., before the first drying cylinder). Withthe paper machines according to documents 1 and 2 this is difficult ornot possible at all because the transfer strip runs on the backing beltas it enters the drying section. In other words:

The fact that the paper web runs according to documents 1 and 2 withoutopen draw through the press section and from the press section into thedrying section offers the advantage of reduced longitudinal stretchingof the moist paper web, but grave disadvantages exist with regard tothreading the paper web into the drying section.

SUMMARY OF THE INVENTION

The problem underlying the invention is improving the paper machinesknown from documents 1 and 2 to the effect that the "threading" of thepaper web into the drying section can be performed with the aid of arope carrier, without the above difficulties while the advantage of thecontinuous paper web backing with the correspondingly reducedlongitudinal stretching of the still moist paper web is to bemaintained.

This problem is solved through the characterizing feature of claim 1.

According to it, the entrance point into the rope carrier is relocatedbehind the leaving point of the paper web from the first dryingcylinder. The entrance point of the rope carrier is preferably arrangedonly in the lower area of the second drying cylinder which is containedinside the backing belt loop (claim 2). This is because during thetransfer process (i.e., during the threading of the paper web into thedrying section) the transfer strip can be permitted, after passing ofthe common looping zone of the paper web and backing belt on the firstdrying cylinder, to run--deviating from the normal tangentialpath--separated from the backing belt running from the first to thesecond cylinder, along a free and curved path toward the secondcylinder. In other words, the entire paper web including the transferstrip runs during the transfer process off the first drying cylinderlater than the backing belt. This makes it possible to deflect thetransfer strip between the first and second drying cylinders from itsnormal path sideways into the path of the rope carrier. During thetransfer process, the remaining paper web runs off downward as scrapfrom the first drying cylinder. In other respects, the threading of thepaper web into the drying section is handled the same as on prior papermachines.

Thus, the invention provides a paper machine combining the followingadvantages:

1. The press section features exclusively double felt presses so that nogranite roll is required. This permits selecting higher pressures thanon prior paper machines.

2. The longitudinal stretch of the paper web in the press section andduring transfer into the drying section is considerably reduced (toabout 1/10 of its previous value). The inevitable remainder isattributable to the fact that the various drives (for the presses anddrying cylinder groups) must run at minor speed differentials. The firstunsupported paper section (open draw) is located only in an area of thedrying section where the paper possesses already a high dry content anda high strength.

3. Using a rope carrier located sideways of the paper web width ispossible, so that threading the paper web into the drying section (whilebacked by a contact belt) is manageable without difficulty even athighest paper machine speeds (in the order of 1400 m/min).

The application of the invention may be particularly advantageous ifaccording to claim 14 one of the roll presses is designed as a so-calledextended gap press. In this case, the paper web adheres, after passingthe press, more firmly to the felt belts than on conventional rollpresses. Additionally, the invention makes it possible to replace, asthe case may be, the previously provided suction press roll by a cheaperregular press roll.

Another device for threading the paper web into the drying section, witha contact felt carrier, is known from document 5, featuring a narrowcarrier belt or rope which is capable of running through the dryingsection along two different paths, either sideways and outside the paperweb width or at the edge of the paper web inside its width. Thus, thecarrier belt can thread the transfer strip into the drying sectionwithin the paper width. Hence it is not necessary to sideways deflectthe transfer strip. However, the carrier belt must be moved out of thepaper web area once the threading is completed. Besides, it must bereintroduced into the paper web area for the next transfer process.Moving the carrier belt in and out represents for the operatingpersonnel an additional, undesirable operation which hinders the swiftrestart of the paper machine after a web break. High operating speedinvolves the additional danger that the carrying belt might break due tofrequently moving it in and out. Therefore, the "theoreticallyconceivable" application of the device according to document 5 on priorpaper machines according to documents 1 and 2 would not result in asatisfactory solution.

Further favorable designs (refer to claims 3 through 13) and embodimentsof the invention will be explained hereafter with the aid of thedrawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a schematic partial view of a paper machine.

FIGS. 1A through 1C shows schematic partial views of other papermachines where the invention has been realized.

FIG. 2 shows a view of the first two drying cylinders of the papermachine presented in FIG. 1, in direction of arrows II--II in FIG. 1.

FIG. 3 shows a schematic side view of the two first drying cylindersalong with one design variant.

FIG. 3Z shows a partial view in the direction of arrow Z in FIG. 3.

FIG. 4 shows a schematic side view of the first drying cylinder usinganother embodiment of the invention.

FIGS. 4X and 4Y show partial views in the direction of arrows X and/or Yin FIG. 4.

FIG. 5 shows an embodiment similar to the example in FIG. 4.

FIG. 5 W shows a view in the direction of arrow W in FIG. 5.

FIGS. 6 and 7 show schematic partial views of the first two dryingcylinders with additional design variants.

FIG. 7V shows a partial view in the direction of arrow V in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 presents the paper web 10 on its way through the paper machine asa dashed line. Of the screen section forming the paper web 10, only asmall section of the endless screen 11 and one of the screen guide rolls12 is visible.

In the press section, the paper web 20 passes first through a roll presscomposed of two press rolls 13 and 14 and two felt belts 15 and 16. Theupper felt belt 15 runs across a lift-off suction roll 17 lifting thepaper web 10 off the screen 11. The two felt belts 15 and 16 preferablyrun together with the intervening paper web 10 first out of the rollpress 13, 14, and at that, up to a suction tube 18 which is arrangedwithin the lower felt loop 16 and ensures that the paper web 10continues to proceed together with the felt belt 16.

A second roll press comprises an upper press roll 23, a belt press unit24, an upper felt belt 25 and a lower felt belt 26. Provided in theupper felt belt 25 is again a lift-off suction roll 27 which lifts thepaper web 10 off the lower felt belt 16 of the first roll press. Thebelt press unit 24 may essentially consist of a fixed roll-shapedsupport body 22, a press shoe 21 and a revolving elastic press belt 20.The press roll 23 and the belt press unit 24 form a so-called extendedgap press featuring a press gap which is extended in the traveldirection of the paper web. The departure of felt belts 25 and 26 fromthe extended press gap may take place in the same fashion as in thefirst roll press. A suction tube 28 may again be provided for thatpurpose.

Instead of using a belt press unit 24, it would also be possible toprovide a normal press roll (as in the first roll press). The cylindersof the press roll are preferably provided with blind bores, grooves orsimilar. Normally, none of the press rolls is designed as a suctionroll.

Only the first three drying cylinders 31, 32, and 33 of the papermachine drying section are visible. A belt carrier 34 (screen, felt orsimilar) meanders across these drying cylinders. The first dryingcylinder 31 is located outside the carrier belt loop, the second dryingcylinder 32 is located inside, the third drying cylinder 33 is againlocated outside etc. The arrangement is such that the carrier belt 34proceeds across the upper cylinder area of the drying cylinders 31 and32 located outside and across the lower cylinder area of the dryingcylinder 32 located inside. Provided inside the belt carrier loop 34 isa lift-off suction roll 37 which separates the paper web 10 from thelower felt belt 26 of the second roll press. The paper web continuesthen together with the carrier belt 34 across the drying cylinders 31,32, 33. In the process, the paper web makes direct contact with thedrying cylinders 31 and 33 located outside. On the inside dryingcylinders 32, conversely, the backing belt 34 is contained between thecylinders and the paper web 10.

As follows from FIG. 1, the paper web is in the entire illustrated partof the paper machine constantly in contact with at least one belt(screen 11; felts 15, 16, 25, 26, or backing belt 34). In other words,an unsupported paper path section and the resulting longitudinal stretchof the paper web are avoided. As can also be seen, none of the pressrolls 13, 14, 23, 24 is in contact with the paper web 10 in the presssection. Thus, none of the press rolls need be a stone roll.

Provided for threading the paper web 10 into the drying section is arope carrier which comprises an upper rope 45 and a lower rope 46. Asfollows from FIG. 2, the ropes 45 and 46 run on the drying cylinders 31,32, 33 in rope grooves 44 which are provided on the tending side edge ofthe drying cylinders. The rope grooves 44 are located outside the paperweb width p and also outside the backing belt width s. The endless ropes45 and 46 return by way of pulleys 47 and 48. Recognizable in FIGS. 1and 2 are the rope pulleys 47 and 48 which are located directly beforethe entrance point 40 of the rope carrier. The entrance point 40 is thatpoint where the common path of the ropes 45 and 46 across the dryingcylinders begins.

The rope pulleys 47 and 48 are inventionally so arranged that theentrance point 40 is located behind the leaving point 39 of the paperweb 10 from the first drying cylinder 31. In the illustrated embodiment,the entrance point 40 of the second drying cylinder 32 is located in thelower cylinder area. The upper rope 45 does not touch the first cylinder31 in the depicted arrangement, for which reason its groove pulley 44remains unused. But it may also happen that the upper rope 45 loopsaround part of the circumference of the first cylinder 31.

Prior to its threading into the drying section, the paper web 10proceeds at full width up to the first drying cylinder 31 and is removedfrom its surface with the aid of a blade 30 and passed into a scrap vat35. Next, a transfer strip 9 is separated with the aid of a (notillustrated) water jet pipe which is located within the screen section.The transfer strip may now be introduced, between the first two dryingcylinders 31, 32, into the entrance point 40 of the rope carrier, withthe strip travelling temporarily along the spatially curved pathillustrated in FIGS. 1 and 2. Thereafter, the transfer strip 9 resumesagain its normal path within the paper web width p. The loop illustratedin FIG. 1, at 9, is eliminated in the process by a small speeddifferential between the two drying cylinders 31 and 32. The firstdrying cylinder possesses for that purpose a drive of its own which isindependent of the other cylinders 32, 33 and illustrated (only inFIG. 1) symbolically by dashed circles representing a drive 81. Lastly,the water jet pipe mentioned above is moved crosswise through the papermachine allowing the transfer strip to widen until the paper web 10 runsat full width through the drying section.

The following applies to FIGS. 1 and 2, and also for the otherembodiments according to FIGS. 1A through C and 3 through 7: a rollerwith a smooth surface could be provided instead of the first dryingcylinder 31. A roller with a plastic coating (for instance Teflon) ispreferably chosen, to which the moist paper web adheres only slightly.The lower drying cylinders (for instance 32) could be replaced bysuction felt guide rollers according to document 6 or by normal, solidguide rolls which, if so required, feature circumferential grooves orsimilar recesses in the roll cylinder.

FIGS. 1A through 1C show that the invention can be used also in variousother press section designs. The initial area of the drying section withcylinders 31, 32, 33, with the backing belt 34 and the scrap vat 35 isunchanged in FIGS. 1A through 1C as against FIGS. 1 and 2.

The embodiment according to FIG. 1A differs from that presented in FIG.1 essentially only by the following characteristics: The upper pressroll 13a of the first roll press is designed as a suction press rollcausing the paper web 10 to run first, behind the press gap, upward withthe upper felt 15. The liftoff suction roll 27a of the second roll pressis arranged within the lower felt 26a and separates the paper web 10from the upper felt 15a of the first roll press.

The press section according to FIG. 1B is essentially designed the sameas that in document 1. Four press rolls 13b, 14b, 23b, and 24b arecombined to a compact press with three press gaps. Modeled on FIGS. 1and 2, the felt belts are marked 15, 16b, 25b, and 26b.

Known as such, an advancement of the press section presented in FIG. 1Bis shown in FIG. 1C. The difference is that a vertical spacing isprovided between the press rolls 13b and 24b and that an additionalpress roll 8 is arranged in the loop of the first upper felt belt 15c,which interacts with the press roll 24b.

FIGS. 3 and 3Z show how the deflection of the transfer strip 9 may beaccomplished with the aid of a so-called air carrier box 50. Such a boxis previously known as such from the patent document 7 and is alsocalled a "web stabilizer." The same as in FIG. 1, the paper web 10proceeds together with the backing belt 34 across the first two dryingcylinders 31 and 32. The rope carrier is present the same as in FIG. 1;but it was omitted in FIGS. 3 and 3Z. The air carrier box 50 is arrangedon the backing belt 34 side not exposed to the paper web 10. In thenormal operation of the paper machine it serves to keep the paper web 10on the backing belt 34. Through a not illustrated line, blasting air isfed to the air carrier box 50 and discharges, through numerous nozzles(arrows 51) distributed across the machine width, on the cylindersurface of the second cylinder 32 opposite to its direction of rotation.Created thereby, in the space between the air carrier box 50 and thebacking belt 34 is a suction which is further increased by a number ofcross channels 52. This vacuum causes the mentioned retention of thepaper web 10 on the backing belt 34.

Provided especially for deflecting the transfer strip 9, on the tendingend of the air carrier box 50, is a separate vacuum zone 53. It islocated at least predominently outside the normal paper web width p. Theseparate vacuum zone 53 is split from the remaining part of the aircarrier box 50 through a sealing strip 54 extending in the traveldirection of the backing belt 34 and making contact with it. The vacuumin the separate zone 53 may be generated either in the same way as inthe remaining part of the air carrier box 50 or with the aid of anadditional suction line 55.

FIGS. 4, 4X and 4Y show an embodiment of a device for the automaticsideways deflection of the transfer strip 9. The blade mentioned aboveand making contact with the underside of the first drying cylinder 31,and which is now marked 30', possesses for that purpose in the path ofthe transfer strip 9 a guide face 56. It has a curvature similar to thatof a plow blade and deflects the transfer strip 9 to the plane of therope carrier, immediately after being stripped from the face of thecylinder 31 by the blade 30'; refer to FIG. 4Y.

More favorable yet, a similar design is illustrated in FIGS. 5 and 5W.In addition to the blade 30 extending as previously across the entiremachine width, a so-called marginal strip blade 60 is provided now.

Firstly, as can be seen from FIG. 5, the blade 30 features a knife 30awhich is mounted on the blade bar 30b with the aid of a clamping strip30c. The marginal strip blade 60 is of a similar design but has smallerdimensions. The length of the knife 61 is only slightly larger than thewidth of the marginal transfer strip 9. The blade body 62 supporting theknife comprises a support arm 63. With it, the marginal strip blade 60is mounted in an only schematically illustrated bearing 64 making theblade 60 (as indicated in FIG. 5) both sideways adjustable (as indicatedin FIG. 5W) and also allowing it to be swiveled by a small angle. Thus,the marginal strip blade 60 may remain sideways outside the paper widtharea during the normal paper machine operation and can be moved duringthe transfer process into the gore between the cylinder 31 and thebacking belt 34 and applied on the face of the cylinder 31. For thesideways deflection of the transfer strip 9, the marginal strip blade 60features a guide element 65 with a guide face 66 which again has acurvature similar to a plow share and deflects the transfer strip 9 intothe path of the rope carrier. The guide element may likewise serve themounting of knife 61 on the blade body 62.

FIG. 6, similar to FIG. 1, shows again the first two drying cylinders 31and 32 and the entrance area of the rope carrier 45 through 48, andadditionally the paper web 10, backing belt 34, and the blade 30.Additionally, there is now a guide roll 69 provided whose length issomewhat larger than the width of the transfer strip 9. The guide roll69 is rotatably mounted on a stud 68; if required, it may be powered.The stud 68 is supported sideways, beside the paper machine by a notillustrated swivel bearing. The axis a of this bearing extendsapproximately perpendicular to the face F of the blade 30 but somewhatoutside the web length of the cylinder 31. In the inoperative position,that is, during the normal operation of the paper machine, the axis ofrotation of the guide roll 69 extends approximately parallel with theaxis of rotation of the first cylinder 31, with the guide roll itselfextending below the cylinder 31 some way into the area of the paper webwidth p. During the transfer process, that is, when the paper webproceeds downward on the cylinder 31 and the blade 30, the guide roll isswiveled upward at an angle around the axis a so that it will take holdof the transfer strip 9 and deflect it sideways, that is, in outwarddirection into the path of the rope carrier 45, 46.

The embodiment illustrated in FIGS. 7 and 7V features the following forthe sideways deflection of the transfer strip 9: Arranged at the leavingpoint 39 of the transfer strip 9 from the first cylinder 31, on thebacking belt 34, is a small suction box 70 which is only slightly widerthan the width of the transfer strip 9. This suction box 70 is duringthe transfer process connected to a not illustrated vacuum force causingthe marginal strip 9 to not continue to proceed with the cylinder 31,but with the backing belt 34. Arranged underneath the suction box 70(also on the backing belt 34 side not exposed to the paper web) is ablasting pipe 71 which is capable of separating the marginal strip 9from the backing belt 34. The blowing direction of the blasting pipe 71is so angled that the marginal strip is being guided sideways andoutward into the path of the rope carrier. To ensure that the marginalstrip will be automatically grabbed by the rope carrier at maximumreliability, another suction box 72 may be arranged below the blastingpipe 71, immediately before the leaving point 49 of the backing belt 34from the second drying cylinder 32, at the extreme outer edge of thebacking belt 34. This box holds the marginal strip 9 on the backing belt34, but with the marginal strip running approximately with its outerhalf outside the backing belt so that it will be safely grabbed by therope carrier. Instead of the blasting tube 71, or in addition to it, asuction box 73 may be arranged sideways beside the tending side edge ofthe backing belt 34, which box will suck the marginal strip in outwarddirection.

What is claimed is:
 1. Paper machine with a press section and a dryingsection and with the following characteristics:(a) The press section isfree of any press roll touching the paper web, that is, there areexclusively double felt roll presses used through which proceeds thepaper web (10) which is to be dehydrated, between two felt belts (15/16;25/26); (b) in the area following the press section, of the dryingcylinders (31, 32 33) of the drying section, the paper web (10) iscarried constantly by a backing belt (34); (c) the orbital path of thebacking belt (34) is tangent to the orbital path of one of the feltbelts (26; 26a; 26b) of the press section, in a way such that ittransfers the paper web (10) without any open draw from the presssection to the drying section; (d) the first drying cylinder (31)following the press section is located outside the endless loop of thebacking belt (34), with the paper web (10) proceeding with the backingbelt (34) across the upper cylinder area of this drying cylinder (31);characterized in that (e) a rope carrier (45,46) located outside thepaper web width (p) and serving the threading of a paper marginal strip(9) into the drying section is so arranged that the entrance point (40)of the marginal strip (9) into the rope carrier is located behind theleaving point (39) of the paper web (10) from the first drying cylinder(31).
 2. Paper machine according to claim 1, characterized in that theentrance point (40) of the rope carrier (45,46) is arranged in the lowerarea of the second drying roller (32) of the drying section locatedinside the backing belt loop.
 3. Paper machine according to claim 1,characterized in that the lower cylinder area of the first cylinder (31)is free of the backing belt (34) and includes a blade (30) for strippingthe paper web (10) off during the threading process.
 4. Paper machineaccording to one of the claims 1, 2 or 3, characterized in that thefirst drying cylinder (31) includes a drive (81) which can be controlledseparately from the other drying cylinders (32, 33).
 5. Paper machineaccording to one of the claims 1, 2 or 3, where an air carrier box (50)is arranged between the first drying cylinders (31 and 32) on thebacking belt (34) side not in contact with the paper web (10), which boxretains the paper web (10) on the backing belt (34) through generating avacuum, characterized in that the air carrier box (50) includes in thearea of the marginal paper strip (9) a separate vacuum zone (53) whichis located at least predominently outside the normal paper web width(p).
 6. Paper machine according to one of the claims 1, 2 or 3,characterized in that in the area of the marginal paper strip (9), belowthe first drying cylinder (31), there is provided a guide device(56;60;69;70-72) which automatically causes the sideways deflection ofthe marginal paper strip (9) from its normal path to a temporarilyspatially curved path into the path of the rope carrier (45, 46). 7.Paper machine according to claim 6, characterized in that the guidedevice is designed as a marginal strip blade (60) which is arranged onthe first drying cylinder (31) and has a curved guide face (66) causingthe sideways deflection of the marginal strip (9).
 8. Paper machineaccording to claim 6, characterized in that the guide device isfashioned as a guide roll (69) whose axis of rotation can be adjusted toan oblique position in accordance with the spatially curved path of themarginal paper strip (9).
 9. Paper machine according to claim 6,characterized in that the guide device (60;69) can be swiveled back andforth between an operating position and an inoperative position. 10.Paper machine according to claim 6, characterized in that the guidedevice is fashioned as a spatially curved guide face (56) which isarranged on a blade (30') located in the lower cylinder area of thefirst cylinder (31) and causes the sideways deflection of the marginalstrip (9).
 11. Paper machine according to one of the claims 1, 2 or 3,characterized in that for sideways deflection of the marginal paperstrip (9) from its normal path into the path of the rope carrier (45,46)the following is provided:(a) located at the leaving point (39) of themarginal strip (9) from the first drying cylinder (31) on the backingbelt (34) side not in contact with the paper web, a marginal stripsuction device (70) for retaining the marginal strip (9) on the backingbelt (34); (b) located in travel direction behind the suction device(70), a separating and deflection device (71), for separating themarginal strip (9) from the backing belt (34) and sideways deflecting ittoward the path of the rope carrier (45;46).
 12. Paper machine accordingto claim 11, characterized in that directly before the run-on point (49)of the backing belt (34) on the second drying roller (32) there islocated, on the extreme outer edge of the backing belt (34), a secondsuction device (72) for again retaining the marginal strip (9) on thebacking belt (34), with the outer area of the marginal strip proceedingin the plane of the rope carrier (45;46).
 13. Paper machine according toclaim 11, characterized in that as separating and deflecting devicethere is arranged, sideways beside the edge of the backing belt (34), atransverse suction device (73).
 14. Paper machine according to claims 1,2 or 3, characterized in that one of the roll presses, is fashioned asan extended gap press, that is, the press gap extended in the traveldirection of the paper web is formed between a normal press roll (23)and a revolving press belt (22) which can be forced on the press roll(20).